Seedless Vascular Plants! Lycophytes and pteriophytes

  • Evolved from the earliest vascular plants, which lacked seeds
  • Pterophyta (Ferns)
  • Psilophyta (Whisk Ferns)
  • Lycophyta (Club Mosses
60 million years ago, seedless vascular plant ancestors grew extremely large, forming the first forests during the Devonian.

Pterophyta (Ferns)

  • Most abundant group of seedless vascular plants (12,000 species)
  • Flourish throughout the world but 75% of species found in the tropics.
  • Typically have an underground stem system referred to as a rhizome.
  • Feathery dissected leaves refereed to as fronds
  • Homosporous, producing distinctive clustered sporangia where meiosis occurs creating spores.
  • At maturity spores are catapulted from plant into damp areas where they may germinate.

Psilophyta (Whisk Ferns)

  • Another phyla of seedless vascular plants.
  • Free water required for process of fertilization in which flagellated sperm unite with egg.
  • Simplest of all extant vascular seedless plants.
  • Form parasitic associations with fungi

Lycophyta (Club Mosses)

  • Crazy little dudes.
  • Abundant in tropics and moist temperate regions.
  • Superficially resemble "true mosses"
  • Either homo- or heterosporous.
  • Leafy stemmed sporophytes.

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